Plunger rod comprising at least three annular elements for a prefilled syringe
Inventors
Baldauf, Wolfgang • Heinrich, Jörg • ZAUNER, Christoph
Assignees
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Publication Number
US-11571520-B2
Publication Date
2023-02-07
Expiration Date
Abstract
A prefilled syringe includes a syringe body filled with a medical fluid, which has a nozzle at a front side, the nozzle being closed with a cap, and which is closed at a rear side with a displaceable plunger; and a plunger rod that can be inserted into the syringe body via the rear side. The plunger rod has a connecting portion at a front side, via whi9ch the plunger rod can be connected to the plunger. At least three annular elements, which extend at least in some sections about a longitudinal axis of the rod, are arranged on a rear side of the connecting portion on the plunger rod in such a manner that they are located in the syringe body when the plunger rod is fully connected to the plunger. The three annular elements support a coaxial connection of the rod to the plunger positioned in the syringe.
Core Innovation
The invention relates to an improved plunger rod for a prefilled syringe and to a corresponding prefilled syringe that includes a syringe body filled with a medical fluid, a nozzle closed by a cap, and a displaceable plunger closed at the rear end. A plunger rod is insertable into the syringe body at the rear end and has a front-end connecting portion that is connectable to the plunger. The plunger rod carries at least three annular elements that extend along a portion of a longitudinal axis next to a rear end of the connecting portion, so that when the connecting portion is fully connected to the plunger the annular elements are situated inside the syringe body.
In the improved prefilled syringe, the annular elements engage the syringe body to promote maintenance of a coaxial position of the plunger rod relative to the plunger while the connecting portion is being connected to the plunger. Wing elements extend radially outwardly and connect the at least three annular elements together, with the wing elements being distributed along a circumference of the plunger rod. The outside diameter of the wing elements within the portion along which the three annular elements extend is smaller than the outside diameter of the at least three annular elements, enabling coaxial guiding support during connection.
The description further includes an oxygen-impermeable overpack that encloses the syringe, with the plunger rod being positioned beside the syringe body within the oxygen-impermeable overpack. The annular-element spacing is defined by a distance R along the longitudinal axis between proximal-most and distal-most annular elements, and the annular elements are arranged at the rear end of the connecting portion. The document also describes guidance and feedback associated with correct versus incorrect seating during connection and discloses that the rear end of the plunger rod is closed off by a flange.
Claims Coverage
The document provides four independent claim groups, covering a prefilled syringe with coaxially guiding plunger rod, an oxygen-impermeable overpack enclosing such a syringe and plunger rod, a plunger rod geometry used in the prefilled syringe, and another formulation of the prefilled syringe including the same coaxial-guiding structural relationships and dimensional constraints.
Prefilled syringe with coaxially guiding plunger rod
A prefilled syringe comprising a syringe body filled with a medical fluid with a nozzle closed by a cap and closed at a rear end by a displaceable plunger, and a plunger rod insertable into the syringe body at the rear end and connectable to the plunger, wherein at least three annular elements extend along a portion of a longitudinal axis next to a rear end of the connecting portion and are situated in the syringe body when the connecting portion is fully connected; wherein the annular elements engage the syringe body to promote maintenance of a coaxial position of the plunger rod relative to the plunger while the connecting portion is being connected to the plunger.
Radially outward wing elements with outside-diameter relationship
Wing elements extend radially outwardly and connect the at least three annular elements together, the wing elements being distributed along a circumference of the plunger rod, wherein an outside diameter of the wing elements within the portion along which the three annular elements extend is smaller than an outside diameter of the at least three annular elements.
Rear-end flange closure of plunger rod
The rear end of the plunger rod is closed off by a flange.
Oxygen-impermeable overpack hermetically enclosing syringe and plunger rod
An oxygen-impermeable overpack comprising a prefilled syringe and a plunger rod, wherein the prefilled syringe and the plunger rod are hermetically enclosed within an interior of the oxygen impermeable overpack.
Annular-element spacing distance R range
The plunger rod includes at least three annular elements arranged on a rear end of the connecting portion at a distance R, wherein 0.5 mm≤R≤20 mm.
Prefilled syringe with screw connection coaxial guidance
A prefilled syringe comprising a syringe body having a front end and a rear end, said syringe body being filled with a medical fluid, a displaceable plunger that closes said body at said rear end, a nozzle at said front end, a cap that closes said nozzle, and a plunger rod that is insertable into said syringe body at said rear end thereof, wherein said plunger rod comprises a connecting portion configured to connect to said displaceable plunger and three annular elements extending along a portion of said longitudinal axis next to a rear end of said connecting portion and extending from a proximal-most annular element to a distal-most annular element, said three annular elements being connected to each other by said wing elements; wherein when said connecting portion is fully connected to said displaceable plunger, said three annular elements are situated in said syringe body and the annular elements engage said syringe body to promote maintenance of a coaxial position of the plunger rod relative to the plunger while the connecting portion is being screwed into the plunger.
Across the independent claims, the inventive concept is a prefilled syringe and plunger rod where at least three annular elements inside the syringe body and radially outward wing elements cooperate to maintain coaxial positioning during connection, including specified outside-diameter relationships, defined annular spacing distance R, and a rear-end flange closure, optionally within an oxygen-impermeable hermetically enclosed overpack.
Stated Advantages
Promotes maintenance of a coaxial position of the plunger rod relative to the plunger while the connecting portion is being connected.
Provides coaxial guiding support during connection by engaging the syringe body with the annular elements.
Provides guidance and feedback associated with correct versus incorrect seating during connection.
Documented Applications
Prefilled syringe use with a plunger rod that supports coaxial guiding during connection and is used with an oxygen-impermeable overpack.
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